Cellulose ester compositions



Patented Aug. 8, 1944 p i UNITED- STATES PATENT OFFICE William H. Holst, Tamaqua, Pal, vassignoi' to Atlas Powder Company, Wilmington, Del a corporation of Delaware No Drawing. Original application March 12, 1940,

Serial No. 323,583. Divided and this application August 22, 1942, Serial No. 455,727

's'cleims. (01.106-176) t The present invention relates to cellulose ester various sorts Another use. is in the field .of'

compositions and more particularly to composimolding compositions where the molded part will tions comprising lower fatty acid esters of cellube subjected to the action of alkali. Many other lose and hexitol tributylidenes. examples could be given of situations in which An object of the invention is to provide a class alkali resistant plastic or resinous compositions of modified cellulose ester compositions which are useful; Among the plastics which may be possess properties of improved plasticity and used are cellulose esters and ethers and various alkali resistance. natural and synthetic resins among which may A particular object is to provide a composibe mentioned specifically the resins of the tion of cellulos mixed esters and hexitoltributyl- Dhenolaldehyde, ester gum, alkyd, coumarone, ldenes.- l polyvinyl, polyamide, methacrylate, polystyrene.-

The above and other objectswil become apparand other equally well-known types. The'butylent from the following description and claims. ld nes an b us d advan a us y w h any This application is a division of my copendtypes of plastics as the sole modifying or plastilng pp at on Serial Number 323,583, fil d cizing agent but in some cases it will be found March 12, 1940 preferable to use the butylidenes in conjunction Cellulose esters of lower fatty acids, such as wit one or of t usual p a c f cellulose acetate, cellulose acetate propionate, modifiers known t0 the and cellulose acetate butyrate, are widely used The modifiers according to the invention can as basesforplastics, film-forming compositions, be D l i 1n itnl-lmber of ways as will b pfilaments and the like. It is known that in their parent o those skilled in this The followunmodified state these esters are unsuitable for 8 Specific examples, O Show methods most practical applications, being deficient in b which t products a b madev Numerbus flexibility, elasticity, and resistance to mechan variations o these methods are possible and 10a! and chemical actions. is not intended to limit the invention to the par- It has been found in accordance t the ticular manner of preparation of the products.

' present invention that the condensation products While the examples are directed to manmtol and ketone'of 4 carbon atoms, are valuable modifying of hexitols, such as mannit l, sorbitol, dulcitol or sorbitol, it will be. understood that the other other isomeric hexitols with an aldehyde or 11933013 can be used- 1 Exliurm 1 agents for the lower fatty acid cellulose esters.

Examples of these condensation products are I Tn'n'bu'tyhdene manmtqlmannitol tri-n-butylidene (from mannitol and 91 (0,5 mol) of mannitol and 120 g. (1.66

. y d y y en mol) ofn-butyraldehyde were mixed with 500 (from sorbitol d yl thyl etone), and mi. of dioxane. To the above solution 25 ml. of mannitol tri isobutylidene (from, manintol and concentrated sulfuric acid were slowly added and so u y 'a dehydeh 4 the entire mass refluxed very gently for one The X l butylidenes are particularly usehour. Upon cooling; two layers.sep'arated out. till as modifiers for plastics. In the first place 40 This mixture was poured into 1500 ml. of water many of the ordinary resins and "plastics are containing 40 g. 01' NaOH (a slight excess over plasticized by these compounds so that they can that necessary to neutralize the E804). The be used to impart flexibility, resistance to crackentire solution was extracted with 100 ml. of ing and the other properties sought in plastic ether and the ether solution dried with compositions. There is, however, a further ad- Drierite". The drier was removed by filtra vantage for the use of these butylidenes in contion and the volatile solvents distilled from the nection with resins and plastics. The hexitol filtrate under reduced pressure. The residue was butylidenes are vry resistant to the action of distiled undervacuum and gave 135 2- Of a liq d alkalies and when mixed with a resin or plastic boiling at 160-161" C. at 3 mm. pressure. The the mixture is found to have high alkali resisty was f t eo y- 1 ance. This property is of considerable prac- Analysis showed the product to consist of tritical advantage as in the case of a coating combutylidene mannitol. The product was compatiposition which is to be used in contact with an ble with cellulose acetate to the extentof 15%,

alkaline solution. Such coating compositions with cellulose acetobutyrate more than 70%,

are used, for example; in lining containers of and with ethyl cellulose more than 50%. These,

at 172-177" C. at 4 mm. pressure.

percentages are based on the weight of cellulose derivative.

. l EXAMPLE 2 Tri-n-bittylidene sorbitol heated on a steam bath for one hour with stirring. At the end of this time the entire mass was poured into 1500 ml. of water containing 40 g. of NaOH. for neutralization. The aqueous solution was extracted with 100 ml. of ether and the ether solution separated and dried with Drierite." volatile solvents were distilled from the filtrate under reduced pressure and the residue was distilled under vacuum. The residue contained two fractions, 68 g. of a liquid boiling at 162-167 C. at 4 mm. pressure and 3'? g. of a liquid boiling Analysis of both fractions showed them to consist of isomeric forms of tributylldene sorbitol. The sorbitol tributylidene has substantially the same physical properties as mannitol tributylidene. .The lower boiling fraction obtained in the condensation was found to be 20% compatible with cellulose acetate. This! product was insoluble in water at 25 C. and at 90 C. was soluble only to the extent. of 0.02 g. per 100 g. water.

EXAMPLE 3 'Tri-z-butylidene mannit bl medium, hence the large excess overthe react-.

ing proportion. The resulting mixture was then heated at 60-6.5 C. ior three hours with stirring.

n At the end of this time all of the mannitol had dissolved. This solution was then mixed with 1500 ml. of water containing 40 g. of NaOH. The excess methyl ethyl ketone separated out and was removed. The water layer was extracted once with 500 ml. of ether and after separa' tion the ether layer was mixed with the methyl ethyl ketone layer previously recovered. This ethereal solution was dried'with Drierite. The drier was then removed from the solution by filtering and the volatile solvents removed from the filtrate by distillation under reduced pressure. The residue was distilled in vacuo. The product consisted of 70 g. (46% theory) of a liquid of boiling point 143-148 C. at 4 mm. pressure. Analysis showed the product to consist of tri-2-butylidene mannitol.

Tri-Z-butylidene mannitol is insoluble in water at 25 C. and soluble to the extent of 0.02 g. per

100 g. of water at 90 C. It is compatible with cellulose acetate to the extent 20%.

Exmn: 4 Tri-Z-butvlidene sorbitol 91 g.- (0.5 mol) of crystalline sorbitol were mixed with 120 g. (150 ml.) of methyl ethyl ketone (1.66 mols) and 500 ml. of dloxane. To this were carefully added 25 ml. of concentrated H2804. The above mixture was heated two hours with stirring on a water bath .at 60 C. At the end oi'- this time got sorbitol were recovered. 75 than'50% with ethyl cellulose.

After filtering oil the drier the.

In this process the ke- The solution was poured into 1500 ml. of water containing 40 g. NaOH for neutralizing the suliuric acid. The entire aqueous mixture was extracted with 1000 ml. of ether and the ethereal solution was dried with Drierite. Alter filtering oil the drier the volatile solvents were removed from the filtrate by distilling under reduced pressure. The residue was distilled under vacuum and gave 57 g. (381% theory) of a liquid boiling at 148-153 C. at 4 mm. pressure. Analysis of the product showed it to consist of tri-2- butylidene sorbitol.

The product was insoluble in water at 25 C. and soluble to the extent of 0.88 g. per 100 g. water at 90 C. The product was also compatible with cellulose acetate to the extent 01' 20%.

EXAMPLE 5 Tri-isobutylidene mannitol 91 g. (0.5.mol) of mannitol and 120 g. (1.66

mol) of isobutyraldehyde were mixed with 500 entire aqueous solution was extracted with 1000 ml. of ether and after separating, the ether solution was dried with Drierite. The drier was re- 1 moved by filtration and the volatile solvents distilled from the filtrate under reduced pressure. The residue was distilled under vacuum and gave 164 g. of a liquid boiling at 159-161 C. at 3 mm. pressure. The yield was 92% of theory. This liquid crystallized upon standing and recrystallization from 90% alcohol gavea crystalline compound, M. P. 46 C.

Tri-isobutylidene mannitol is insoluble in water at 25 C. and soluble to the extent or 0.05 g./100 g. water at 95 C.

This compound is compatible (without causingblushing) to the extent of 30% with cellulose nitrate, 20% with cellulose acetate, more than 70% with cellulose acetobutyrate, and more than with ethyl cellulose.

EXAMPLE 6 Tri-zsobutylidene sorbitol 91 g. (0.5 mol) of crystalline sorbitol and 120 A g. (1.66 mol) of isobutyraldehyde were mixed with 500 ml. of dioxane and to this were added 25 ml.

of concentrated H2804. This mixture was heat ed at C. for one-half hour with stirring. At

' the end of this time the entire mass was poured sure and the residue. was distilled under vacuum.

This gave 145 g.-of a liquid boiling at 156-8 C./4 mm. The yield was 82% of theory.

Tri-isobutylidene sorbitol is insolube in water at 25 C. and soluble to the extent of 0.08 g./100

g. water at C. This compound is compatible (withoutcausing blushing) to the extent of more than 50% with cellulose nitrate, 20% wit than 70% with cellulose acetobutyrate, and more ellulose acetate, more,

containing it.

A series of four lacquers was made up from cellulose derivatives and tri-isobutylidene mannitol added as a plasticizer. The cellulose derivatives used were cellulose nitrate, cellulose acetate, cellulose acetobutyrate, and ethyl cellulose.

Each lacquer comprised ten parts of the celluened"by means" of hexamethylene-tetramine. Ar-

ticles molded from this powder are -found to have.

. greatiy'improved resistance to alkalies. For .com-

parison small. discs molded of this mixed composition canbe tested alongside of similar discs moldedffromthe straight molding powder. The

lose derivative dissolved in 100 parts of a solvent mixture composed of 75 parts acetone and 25. partsethyl lactate. To these solutions 20% triisobutylidene mannitol was added, based on the amount of cellulose derivative.

Coating films produced from each of these four lacquers possessed good flexibility. Tested for adhesion the lacquers were spread upon brass plates and in each case the film showed good quers was made up containing the same cellulose derivatives and using a standard plasticizer, namely dibutyl phthalate. The plasticizer was here employed in the same proportion as the triisobutylidene mannitol, that is in the amount of 20% based on the cellulose derivative. Fromilexibility and adhesion tests on these lacquers it: became apparent that tri-isobutylidene mannitol was as good as or better than dibutyl phthalate as a plasticizer. In addition to its plasticizing e'ilect the tri-isobutylidene mannitol imparted a high degree of alkali resistance to the lacquer Exlurrm: 8

In a manner similar to the tests of Example 7 the effectiveness of tri-isobutylidene sorbitol was tested for use in lacquers and the properties of the resulting lacquers compared with lacquers containing no plasticizer and lacquers containing dibutyl phthalate as a. plasticizer; I

As a result of the tests it appeared that in every case a lacquer containing tri-isobutylidene sorbitol was superior to a lacquer containing noplasticizer. It further appeared that tri-isobutylidene sorbitol was as good a plasticizer for the cellulose derivatives tested as dibutylphthalate, taking into consideration appearance, flexibility and adhesion of the resulting film. Tri-isobutylidene mannitol appeared to be slightly better as a a plasticizer for ethyl cellulose, cellulose acetate,

and cellulose acetobutyrate.

The lacquers containing tri-isobutylidene sorbitol had very good alkali resistance.

\ Exsmna 9 As an example of a molding'compound may be cited the following: Bakelite molding power of the grade known as BM-120 has incorporated therewith 10% of tri-isobutylidene' mannitol. Resin BM-120 is a product of the Bakelite Corporation and is a mixture of a fusible phenolaldehyde novolak resin (of. Carleton Ellis "The Chemistry of Synthetic Resins, 1935 edition, pp. 316-322) and wood flour, the resin being hardtests consist of. subjecting the discs to the; action of alkali solutions, for example; sodium hydroxide of different. strengths, over periods of several days. The. discs are then weighed to determine increase. in weight, increase in weightlndicating lack of resistance; the alkalisolutions are ,ex-

amined for increase in color, whichis an: indication of theextent to which the alkali hasattacked the disc; and the physical conditionof the disc is noted. In each case the molding composition containing tri-isobutylidene mannitol is outstandingly" resistant. to alkali, whereas the un- 7 mixed composition is rapidly attacked and at the. higher alkali concentration is: even disintegrated.

Similar results as to improved-alkali resistance are obtainable with the other butylidenes of' the present invention. Other resins: or plastic materials arealso improved as to their alkali. re-

sistance by the addition of one of. the. butylidenes described herein.

Drierite referred to .above. in the; examples is a. trade name for anhydrous calcium sulfate. and x the material is used as a dehydrating agent.

The acetals and ketals of the invention are virtually insoluble in water, even at advanced temperatures, so that plastic or resin composi-' tions containing them are not subject to'loss as a result of leaching when they are brought into contact with water. the invention have very low volatilities and so the plastic or resin composition in which they are present as modifiers retains its modified properties for long periods of time.

The-invention is not to be taken as limited by the above specific examples .nor by the mode of preparation of the compounds. The invention which it is desired to protect is limited only by 45 the scope .of the following claims.

I claim: e l. A composition comprising a lower fatty acid cellulose ester and a hexitol tributylidene.

2. A composition comprising a lower fatty acid cellulose ester and a hexitol tri-2-butylidene. 3. A composition comprising a cellulose mixed ester of acetic acid and an acid of the group consistingof propionic and butyric acids, and a hexitol tri-hutylidene. I

4. A composition comprising a-cellulose mixed ester of acetic acid and an acid of the group consisting of propionic and butyric acids, and a hexitol tri-Z-butylidene.

. 5. A composition comprising a cellulose mixed ester of acetic acid and an acid of the group consisting of propiohic and butyric acids, and a sorbitol tri-Z-butylidene.

. cellulose ester and mannitol tri-isobutylidene.

HOLST.

Likewise, the modifiers of I 

